EP0623897A1 - Portable object and method for manufacturing - Google Patents

Abstract

The present invention relates to a portable object and the method for manufacturing such an object. The portable object including in a plastic support (2) a cavity (26, 27) intended to receive a micromodule assembly including a conductive wafer (11) which includes areas which are electrically insulated from one another and which is connected electrically to a semiconductor integrated circuit (13) which includes at least one storage function, is characterised in that the cavity (26, 27) has a contour (261, 271) shaped as a succession of adjoining arcs of small amplitude relative to a contour mid-line whose shape matches the shape of the wafer, the said contour of the housing forming a rake of 10 degrees relative to a direction perpendicular to the surface of the support (2). <IMAGE>

Description

The present invention relates to a portable object and the method of manufacturing such an object.

Methods of manufacturing portable objects, such as micro-circuit cards, are known, in which the integrated chip-circuit assembly forming what the skilled person calls a button or a micromodule is arranged in a housing obtained. by assembling several layers of plastic sheets, one of which is cut to the dimensions of the patch and at least one other layer to the dimensions of the integrated circuit. The different sheets are then joined together before the micromodule is put in place using a resin or an adhesive in the cavity thus formed. This process is expensive because it involves many steps.

Another method consists in hot deforming a plastic sheet of greater thickness and inserting the button assembly therein. This second process is detrimental for the semiconductor of the micromodule which is brought to a temperature which is sometimes too high whereas the first process which gives a good quality result has the disadvantage of being too expensive.

Finally, the last inexpensive process consists in milling a housing intended to receive the button in a plastic sheet of sufficient thickness and then fixing it in this housing using a resin. However, in this process, the space available between the button and the cavity is large and the quantity of glue to be used is not negligible. The surface condition of the card which results from the use of this method is relatively poor.

A first object of the invention is therefore to propose a portable object whose surface condition, at level of the area between the contact pad and the card is of higher quality and requires the use of a lesser amount of glue.

This object is achieved by the fact that the portable object comprises in a plastic support a cavity intended to receive a micromodule assembly comprising a conductive patch comprising zones electrically isolated from each other and to which an integrated circuit is electrically connected to semiconductor comprising at least one memory function is characterized in that the cavity has a contour shaped in a succession of contiguous arcs of small amplitude with respect to an average contour line of shape adapted to the shape of the patch, said contour of the housing forming a draft of 10 degrees relative to a direction perpendicular to the surface of the support.

According to another particularity, the cavity comprises two concentric or non-concentric recesses, the first of which has a larger surface than the second and is of less depth than the second.

According to another particular feature, the first recess has a depth less than the sum of the thickness of the conductive patch and the thickness of the hot-melt tape associated with the conductive patch.

According to another particular feature, the clearance angle and the depth of the first recess are calculated to absorb the volume of hot-melt adhesive corresponding to the difference in dimension between the depth of the first recess and the thickness of the pellet-hot-melt ribbon assembly.

According to another particularity, the depth is less than 0.05 to 2 hundredths of a millimeter.

According to another particularity, the depth is less than 2 hundredths of a millimeter.

According to another particularity, the integrated circuit is fixed in the second recess by an adhesive with semi-rapid setting loaded with elastomer.

According to another particularity, the glue is of the cyanoacrylic type.

In another feature, the glue is a resin.

According to another particular feature, the patch is fixed in a first housing by a hot-melt adhesive.

According to another particular feature, the ends of the arcs define a contour whose dimensions are, relative to the dimensions of the mean contour line, reduced by a value between 1/1000 th and 10 / 1000th.

According to another particular feature, the dimensions are preferably reduced by 3/1000 th.

Another object of the invention is to propose a method of manufacturing portable objects according to the first aim.

• une étape de mesure, à l'aide d'un faisceau laser, de l'épaisseur de matière formant le support de la carte dans laquelle une cavité doit être creusée pour recevoir l'ensemble micromodule ;
• une étape de calcul de la distance de la descente d'une broche de fraiseuse par rapport à un plan fixe constitué par la surface supérieure du support formant la carte ;
• une étape de commande des déplacements d'une fraise en queue d'aronde, dont la queue d'aronde correspond à l'angle de la dépouille de la cavité, pour former le contour conformé en une succession d'arcs jointifs ;
• une étape de collage de l'ensemble micromodule sur le support.

This object is achieved by the fact that the method of manufacturing portable objects includes:

• a step of measuring, using a laser beam, the thickness of material forming the support of the card in which a cavity must be dug to receive the micromodule assembly;
• a step of calculating the distance of the descent of a milling spindle from a fixed plane constituted by the upper surface of the support forming the card;
• a step of controlling the movements of a dovetail cutter, the dovetail of which corresponds to the angle of the draft of the cavity, to form the contour shaped in a succession of contiguous arcs;
• a step of bonding the micromodule assembly to the support.

According to another particularity, the bonding step comprises a step of depositing a defined quantity of glue with semi-rapid setting in the second recess of the cavity to ensure the attachment of the integrated circuit to a semiconductor of the assembly micromodule.

According to another particular feature, the bonding step further comprises a step of heating the conductive patch comprising zones electrically isolated from one another and provided with a hot-melt tape in a part surrounding the semiconductor.

According to another particularity, the process comprises, prior to the fixing of the semiconductor integrated circuit, a step of depositing a hot-melt ribbon, provided with cutouts of a size sufficient to surround the semiconductor, on the conductive ribbon which comprises a succession of cut conductive pads each of which is electrically connected to a semiconductor and a step of separation of the micromodule assembly for placement in the cavity of the support.

According to another particular feature, the step of separating the micromodule assembly is carried out using a punch with a convex surface cooperating with a matrix, the opening of which is obstructed by a receiving cup (81) intended to receive the mechanically deformed micromodule.

According to another particularity, the micromodule assembly positioned on a cup is brought to a positioning station in the cavity of the support for, by action of the pusher, ensuring the descent of the micromodule into the cavity arranged opposite the concavity of the cup of dimension smaller than the dimension of the outline of the housing provided in the support (2).

• la figure 1A représente une vue de dessus de la cavité formée dans le support de l'objet portatif ;
• la figure 1B représente une vue en coupe de cette même cavité formée dans le support de l'objet portatif ;
• la figure 1C représente une particularité du contour de la cavité ;
• la figure 1D représente une vue de côté d'un micromodule destiné à être encastré dans la cavité ;
• la figure 2A représente une vue de côté d'un premier poste permettant la mise en oeuvre d'une partie des étapes du procédé ;
• la figure 2B représente une vue de côté d'un deuxième poste permettant la mise en oeuvre des autres étapes du procédé ;
• la figure 3A représente une vue en coupe d'un troisième poste permettant la mise en oeuvre d'une variante du procédé ;
• la figure 3B représente une vue en coupe d'un quatrième poste permettant la mise en oeuvre du procédé.

Other features and advantages of the present invention will appear more clearly on reading the description below made with reference to the accompanying drawings in which:

• FIG. 1A represents a top view of the cavity formed in the support of the portable object;
• Figure 1B shows a sectional view of the same cavity formed in the support of the portable object;
• Figure 1C shows a feature of the outline of the cavity;
• Figure 1D shows a side view of a micromodule intended to be embedded in the cavity;
• FIG. 2A represents a side view of a first station allowing the implementation of part of the steps of the method;
• FIG. 2B represents a side view of a second station allowing the implementation of the other steps of the method;
• FIG. 3A represents a sectional view of a third station allowing the implementation of a variant of the method;
• FIG. 3B represents a sectional view of a fourth station allowing the implementation of the method.

FIG. 1A represents a top view of the contour (261) of a cavity formed in a plastic support, this contour of the edge (261) of the cavity is formed of a succession of contiguous arcs thus defining a mean line of contours whose shape corresponds in Figure 1 to that of a square. These contiguous arcs have a height h = 0.04 mm and a length l = 0.5 mm, as shown in FIG. 1C. In FIG. 1B, it can be seen that the upper edge formed on one side of the contour (261) is arranged, with respect to the upper edge of the contour located opposite, at a distance d - h = 11.57 mm , which corresponds to the dimension (d = 11.61 mm) of the conductive pad (11), as shown in FIG. 1D, and reduced by the height (h) of the arc. The bottom of a first recess (26) forming the cavity is set back relative to the upper edge (261) of this cavity and so as to form a draft angle of 10 ° relative to the upper surface of the sheet of plastic material (2) forming the support of the portable object. A second recess (27) completes the cavity, this second recess is concentric or not with respect to the first, of smaller surface and greater depth than the first recess (26). This second recess (27) also includes a contour formed by a succession of arcs of a circle so as to define a contour line (271) whose upper edge is offset with respect to the bottom of the recess to form a draft d '' an angle of 10 °. The apex of the arcs of an upper edge of the first recess (26) is arranged relative to the apex of the arcs of the other upper edge of the first recess at a distance (d + h) corresponding to the width (d) of the patch increased by the height (h) of an arc. Finally, at the bottom of the first recess (26), the distance between the vertices of the arcs of the opposite contour lines corresponds to the width (d) of the patch increased by 3 times the height (h) of an arc. The depth (p) of the first recess (26) is less than the thickness of the conductive pad assembly (11) hot-melt tape (12) by a value which corresponds to 3/1000 th of the sum of these thicknesses (e₁ , respectively e₂). The particular conformation of the edges (26) of the cavity makes it possible to produce a phenomenon of clipping on the edges (110) of the patch (11) and the free spaces between the edge (110) of the patch (11) and the arcs delimiting the bottom of the first recess (26) of the cavity makes it possible to absorb the surplus of hot-melt adhesive when the upper surface of the pellet (11) is brought by heating in the plane of the upper surface of the plastic part (2) forming the support of the card.

In an advantageous variant, the edges (110) of the patch form a bias, the angle (b) of which is perpendicular to the surface of the contacts is at most equal to the clearance angle of the recesses (26, 27).

The portable object, described in connection with FIGS. 1A to 1D, is manufactured by the method explained using FIGS. 2A and 2B. This method comprises a first step implemented on the device represented in FIG. 2A which consists in measuring the thickness of the support (2) forming the card using a laser (3) which communicates the measurement information to a digital control device (4) for consequently controlling the movement of the milling head (52) at the end of which is placed a dovetail cutter (53) whose draft forms an angle of 10 ° relative to the vertical. The vertical movement of the cutter (z) is controlled by digital control (4) according to the thickness measurement (x) made by the laser (3) so that the depth (p) of the first recess (26) of the cavity corresponds exactly to the desired depth on the one hand and on the other hand that the dimensions of the contour of the first recess of the cavity also correspond to the desired values. Then the digital control (4) controls the movement of the milling head (52) to make the second recess (27). Once this operation has been carried out, the support (2) forming a card is brought to a second station shown in FIG. 2B, after having been provided at an intermediate station with a micromodule assembly (11, 12, 13) formed of a conductive patch (11), comprising electrically insulated zones and conductive zones of a semiconductor (13) and a strip (12). On the pad (11) is mounted a semiconductor electronic component (13) which is itself connected electrically to the various conductive areas of this conductive patch, as is known to those skilled in the art. A hot melt tape (12) having at the location corresponding to that of the semiconductor (13) an orifice clearing the passage for the semiconductor is disposed on each wafer (11).

The micromodule (11, 12, 13) is prepared from a ribbon (10) comprising the conductive zones and electrically insulated zones and on which semiconductors (13) and the hot-melt ribbon (12) will have been placed. This ribbon (10) will be cut into a micromodule by cuts at regular steps made by a punch (71) the front face of which has a recess (712) to prevent the semiconductor (13) from being crushed and forms a curved surface. (711), preferably either cylindrical or in the form of a spherical cap. This punch by meeting the ribbon (10) will deform it and bring it to bear on the die (72) of the cutting tool to cut the micromodule (11, 12, 13) shown in solid lines in the figure. 3A. The advancement of the punch (71) will push the micromodule into a receiving cup (81) located on the other side of the die (72) and in which is mounted a pusher consisting of a plate (821) of a cylindrical part (822) and a concave surface (8231) formed on a washer (823) disposed at the lower end of the cylinder (822), so that the washer (823) bears on the shoulders (811) of the welcome cup when the springs (824) relax. The punch (71) with a spherical surface of radius (R) or a cylindrical surface of the same radius makes it possible to obtain micromodules comprising, according to the variant of FIG. 1D, an edge (110) at an angle. This micromodule (11, 12, 13) will be maintained in the receiving cup (81) by undergoing a mechanical deformation which gives it a bending, as shown in FIG. 3A.

The entire reception cup (81) - pusher tool (82), micromodule (11, 12, 13) pinched in the reception cup (81) is then brought to a fourth station, shown in FIG. 3B. At this fourth station, a support element (2) pre-cut in the form of a card and in which the cavities (26, 27) have been formed is placed opposite the cup (81) and the push tool (82). This pusher tool (82) is actuated downwards by a descending rod (825) which causes the displacement of the concave pusher (823) thus ensuring the descent of the micromodule into the housing (26, 27). In FIG. 3B, it can be realized that the distance separating the vertical walls (812) from the cup (81) is less than the dimensions of the first recess (26) made in the support (2) of the card, so as to allow a easy installation of the micromodule in its housing thus ensuring self-centering of the latter in the recess (26) when the micromodule becomes naturally flat after having left the cup (81). This positioning of the micromodule (11, 12, 13) makes it possible to avoid having to position the precise housing produced beforehand on the milling machine with very high precision under the inserting tool to maintain high quality. inserting. In addition, the use of a domed punch makes it possible to obtain edges (110) at an angle, as shown in FIG. 1D.

In an alternative embodiment, one could consider using a punch with a flat front face (711) with the recess (712) and cutting the micromodule with a die (72) whose dimension corresponds to that of the first recess (26 ) in the vicinity of the cutting surface and the internal surfaces (720) of which have a taper allowing the micromodule to be brought gradually by deformation to the dimensions of the cup (81) for transporting the micromodule to the next station. In in this case, the edges of the micromodules would not be biased.

Before installing the button or module thus formed, the manufacturing machine will have previously deposited a drop of glue (25), consisting either of a resin, or of a cyanoacrylic glue to effect a semi-rapid fixing of the integrated circuit in the housing (27) of the card (2). Then, at the station in FIG. 2B, the card is positioned on a reference support (62), which comprises, in the zone corresponding to the location of the micromodule (11, 12, 13), an air duct (63) of cooling formed in the support (62). Opposite this support referenced (62) is a head (6) having configurable heating electrodes. This head (6) is itself provided in its center with a housing (61) filled with non-conductive material of heat so as to avoid overheating of the central zone of the micromodule corresponding to that where the circuit is located on the back integrated. The heating head (6) is lowered and then applied with a certain pressure on the micromodule assembly to, on the one hand effect the melting of the hot-melt ribbon (12) and on the other hand, by pressure, cause the evacuation of the surplus hot melt glue in the direction of the arcs of the cavity.

The advantage of the method is that the button assembly put in place in the cavity does not risk escaping from it during a rapid and brutal transfer from a work station to another station, for example, from the micromodule placement station, to the next pressing station.

The method also makes it possible to maintain the chip by clipping in order, on the one hand to improve the presentation of the insert and, on the other hand, to use other bonding means than those currently used.

Thanks to this clipping effect, we do not have to use quick-setting adhesives (2 to 20 seconds) offering shear resistances on steel from 14 to 22 MPA less efficient than those with semi-rapid setting (10 seconds to 2 minutes) resistant to peeling, impact and loaded with elastomer, offering flexibility characteristics of resilience and shear resistance on steel from 22 to 30 MPA. This quality of adhesive can also be applied to the bonding of the tablet.

Furthermore, this process has the advantage of making it possible to constitute a natural reservoir of the excess glue to avoid a deburring operation and also to ensure better attachment of the chip to the support thanks to this toothing which ultimately resembles straight knurling. The undercut also offers the advantage, once the glue has hardened, of only allowing the micromodule or the chip to be torn off by breaking the card.

It is obvious that the invention has been shown with a cavity having an average contour of square shape but that it also applies to all the average contour lines of rectangular, round, oblong shape and for all thicknesses of pellet and hot melt tape.

Other modifications within the reach of the skilled person are also part of the spirit of the invention.

Claims (18)

Portable object comprising in a support (2) of plastic material a cavity (26, 27) intended to receive a micromodule assembly comprising a conductive pad (11) comprising zones electrically isolated from each other and to which an integrated circuit is electrically connected (13) semiconductor comprising at least one memory function, characterized in that the cavity (26, 27) has a contour (261, 271) shaped in a succession of contiguous arcs of small amplitude compared to an average line of contour of shape adapted to the shape of the pellet, said contour of the housing forming a draft of 10 degrees relative to a direction perpendicular to the surface of the support (2). Portable object according to claim 1, characterized in that the cavity (26, 27) comprises two concentric or non-concentric recesses, a first (26) of larger area than the second is of shallower depth than the second. Portable object according to claim 1 or 2, characterized in that the first recess (26) has a depth (P) less than the sum of the thickness (e₁) of the conductive pad (11) and the thickness (e₂ ) hot melt tape (12) associated with the conductive pad. Portable object according to claim 1 or 2, characterized in that the clearance angle and the depth (P) of the first recess (26) are calculated to absorb the volume of hot-melt adhesive corresponding to the difference in dimension between the depth (P ) of the first recess and the thickness (e₁ + e₂) of the pellet-hot-melt ribbon assembly (11, 12). Portable object according to claim 3 or 4, characterized in that the depth (P) is less than 0.05 to 2 hundredths of a millimeter. Portable object according to claim 3 or 4, characterized in that the depth (P) is less than 2 hundredths of a millimeter. Portable object according to one of the preceding claims, characterized in that the integrated circuit (13) is fixed in the second recess (27) by an adhesive with semi-rapid setting loaded with elastomer. Portable object according to claim 7, characterized in that the adhesive is of the cyanoacrylic type. Portable object according to claim 7, characterized in that the adhesive is a resin. Portable object according to claim 1, characterized in that the tablet (11) is fixed in a first housing (26) by a hot-melt adhesive. Portable object according to claim 1, characterized in that the ends of the arcs define a contour, the dimensions of which, relative to the dimensions of the mean contour line, are reduced by a value between 1/1000 th and 10 / 1000th. Portable object according to claim 11, characterized in that the dimensions are preferably reduced by 3/1000 th. Method for manufacturing portable objects according to one of the preceding claims, characterized in that it comprises: a step of measurement using a laser beam of the thickness of material forming the support (2) of the card in which a cavity (26, 27) must be dug to receive the micromodule assembly (11, 12, 13); - A step of calculating the descent distance of a spindle (52) of milling machine relative to a fixed plane constituted by the upper surface of the support (2) forming the card; a step for controlling the movements of a dovetail cutter (53), the dovetail of which corresponds to the angle of the clearance of the cavity (26, 27), to form the outline (261, 271) shaped like a succession of contiguous arches; - A step of bonding the micromodule assembly (11, 12, 13) on the support (2). Method according to claim 13, characterized in that the bonding step comprises a step of depositing a defined quantity of glue with semi-rapid setting in the second recess (27) of the cavity to ensure the attachment of the integrated circuit to semiconductor (13) of the micromodule assembly. A method according to claim 13 or 14, characterized in that the bonding step further comprises a step of heating the conductive pad (11) comprising zones electrically isolated from each other and provided with a hot-melt tape (12) in a part surrounding the semiconductor (13). Method according to one of claims 13 to 15, characterized in that, prior to the fixing of the integrated semiconductor circuit (13), a step of depositing a hot-melt tape (12), provided with cutouts of sufficient size to surround the semiconductor (13) on the conductive tape which comprises a succession of cut conductive pads (11) each of which is electrically connected to a semiconductor and a step of separating the micromodule assembly for placement in the cavity of the support (2). Method according to claim 16, characterized in that the step of separating the micromodule assembly (11, 12, 13) is carried out using a punch with a convex surface cooperating with a matrix whose opening is obstructed. by a receiving cup (81) intended to receive the mechanically deformed micromodule. Method according to one of claims 16 or 17, characterized in that the micromodule assembly positioned on a cup (81) is brought to a position for positioning in the cavity (26, 27) of the support (2) for, by action of the pusher (82), ensure the descent of the micromodule into the cavity arranged opposite the concavity of the cup of dimension smaller than the dimension of the outline of the housing provided in the support (2).

Images